PFO closure devices and related methods of use

ABSTRACT

Devices and methods for sealing a passageway formed by a patent foramen ovale (PFO track) in the heart are provided. One method includes providing an abrading device to the PFO track and abrading the tissue within the PFO track. The abraded tissue forming the PFO track is then held together under pressure, either via lowering right atrial pressure or via applying suction to the septum primum to pull it into apposition against the septum secundum. After a sufficient period of time, the pressure is released and the abraded tissue heals to form a robust seal over the PFO track. Additionally, several devices are provided which can be placed into the PFO track to apply adhesive to the walls of the PFO track. The devices may or may not be left within the PFO track. If the devices are not left within the PFO track, the walls of the PFO track, covered with adhesive, are brought into apposition with one another and adhered together. If the device is left within the PFO track, the device is flattened from an expanded configuration to a flattened configuration, and the walls of the PFO track, adhering to the outer surface of the device, are pulled toward each other as the device flattens. The device may also include interior structure to hold the device in a flattened configuration.

This application is a continuation of U.S. application Ser. No.10/138,565, filed May 6, 2002, entitled “PFO Closure Devices and RelatedMethods of Use,” the entire disclosure of which is incorporated hereinby reference.

FIELD OF THE INVENTION

This invention relates to devices for closing a passageway in a body,for example a patent foramen ovale in a heart, and related methods ofusing such closure devices for sealing the passageway.

BACKGROUND OF THE INVENTION

FIG. 1 shows a short-axis view of the heart at the level of the rightatrium (RA) and left atrium (LA), in a plane generally parallel to theatrio-ventricular groove, and at the level of the aortic valve. Thisview is looking from caudal to cranial. FIG. 1 also shows the septumprimum (SP), a flap-like structure, which normally covers the foramenovale, an opening in the septum secundum (SS) of the heart. In utero,the foramen ovale serves as a physiologic conduit for right-to-leftshunting of blood in the fetal heart. After birth, with theestablishment of pulmonary circulation, the increased left atrial bloodflow and pressure presses the septum primum (SP) against the walls ofthe septum secundum (SS), covering the foramen ovale and resulting infunctional closure of the foramen ovale. This closure is usuallyfollowed by anatomical closure of the foramen ovale due to fusion of theseptum primum (SP) to the septum secundum (SS).

Where anatomical closure of the foramen ovale does not occur, a patentforamen ovale (PFO) is created. A patent foramen ovale is a persistent,usually flap-like opening between the atrial septum primum (SP) andseptum (SS) of a heart. A patent foramen ovale results when eitherpartial or no fusion of the septum primum (SP) to the septum secundum(SS) occurs. In the case of partial fusion or no fusion, a persistentpassageway (PFO track) exists between the septum primum (SP) and septumsecundum (SS). This opening or passageway is typically parallel to theplane of the SP, and has a mouth which is generally oval in shape. FIG.2 shows the opening of the PFO track viewed from an end of the track.Normally the opening is relatively tall, but quite narrow. The openingmay be held closed due to the mean pressure in the LA being typicallyhigher than in the RA. In this manner, the SP acts like a one-way valve,preventing fluid communication between the right and left atria throughthe PFO track. However, at times, the pressure may temporarily be higherin the RA, causing the PFO track to open up and allow some fluid to passfrom the RA to the LA, as indicated in FIG. 3. Although the PFO track isoften held closed, the endothelialized surfaces of the tissues formingthe PFO track prevent the tissue from healing together and permanentlyclosing the PFO track. As can be seen in FIG. 4, (a view from line “C-C”of FIG. 1), the SP is firmly attached to the SS around most of theperimeter of the Fossa Ovalis, but has an opening along one side. The SPis often connected, as shown, by two or more extensions of tissue alongthe sides of the PFO track.

Studies have shown that a relatively large percentage of adults have apatent foramen ovale (PFO). It is believed that embolism via a PFO maybe a cause of a significant number of ischemic strokes, particularly inrelatively young patients. It has been estimated that in 50% ofcryptogenic strokes, a PFO is present. Blood clots which form in thevenous circulation (e.g., the legs) can embolize, and may enter thearterial circulation via the PFO, subsequently entering the cerebralcirculation, resulting in an embolic stroke. Blood clots may also formin the vicinity of the PFO, and embolize into the arterial circulationand into the cerebral circulation. Patients suffering a cryptogenicstroke or a transient ischemic attack (TIA) in the presence of a PFOoften are considered for medical therapy to reduce the risk of arecurrent embolic event.

Pharmacological therapy often includes oral anticoagulants orantiplatelet agents. These therapies may lead to certain side effects,including hemorrhage. If pharmacologic therapy is unsuitable, open heartsurgery may be employed to close a PFO with stitches, for example. Likeother open surgical treatments, this surgery is highly invasive, risky,requires general anesthesia, and may result in lengthy recuperation.

Nonsurgical closure of PFOs is possible with umbrella-like devicesdeveloped for percutaneous closure of atrial septal defects (ASD) (acondition where there is not a well-developed septum primum (SP)). Manyof these conventional devices used for ASDs, however, are technicallycomplex, bulky, and difficult to deploy in a precise location. Inaddition, such devices may be difficult or impossible to retrieve and/orreposition should initial positioning not be satisfactory. Moreover,these devices are specially designed for ASDs and therefore may not besuitable to close and seal a PFO, particularly because the septum primum(SP) overlaps the septum secundum (SS).

SUMMARY OF THE INVENTION

In accordance with the invention, methods and devices for closing apassageway in a body, and more specifically closing a patent foramenovale (PFO), are provided.

According to one aspect of the invention, a method of sealing apassageway in a heart is provided. The method includes advancing anabrasion device into the passageway to be sealed, abrading at least aportion of the tissue surfaces forming the passageway, withdrawing theabrasion device from the passageway, and forcing abraded portions of thetissue surfaces of the passageway against one another for a period oftime.

According to another aspect of the invention, a device for sealing apassageway in a human body is provided. The device comprises a catheterhaving an distal portion, and at least one suture lumen, the at leastone suture lumen containing a suture having an anchor at an end of thesuture.

According to yet another aspect of the invention, an assembly forsealing a passageway in a human body is provided. The assembly includesa delivery catheter, a suture connected to a barbed anchor, and asupport tube configured to surround and support the suture.

According to a further aspect of the invention, a method of sealing apassageway in a heart is provided. The method comprises advancing ahollow tubular structure into the passageway to be sealed, engaging thewalls of the passageway with the hollow tubular structure, andflattening the hollow tubular structure.

According to another aspect of the invention, a method of sealing apassageway in a heart includes advancing a catheter into the passageway,applying adhesive to the walls of the passageway, withdrawing thecatheter from the passageway, and forcing portions of the walls of thepassageway against one another for a period of time sufficient to allowthe adhesive to at least partially cure.

According to yet another aspect of the invention, a method of sealing apassageway in a heart is provided. The method comprises advancing adelivery device having an expandable end into the passageway, whereinthe delivery device includes at least two suture lumens, each suturelumen having an open end positioned in the passageway when the deliverydevice is advanced into the passageway, expanding the expandable end,advancing a suture-anchor assembly out of the end of each suture lumen,penetrating the tissue forming the passageway with an anchor of eachsuture-anchor assembly, and pulling the passageway closed with theanchored sutures.

According to another aspect of the invention, a method of sealing apassageway between a septum primum and a septum secundum in a heart isprovided. The method includes advancing a delivery catheter into theright atrium, advancing an anchor and suture assembly out of the delivercatheter, and passing the anchor and suture assembly through the septumsecundum and through the septum primum.

Additional advantages of the invention will be set forth in part in thedescription which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention will be realized and attained by meansof the elements and combinations particularly pointed out in theappended claims.

The foregoing general description and the following detailed descriptionare exemplary and explanatory only and are not restrictive of theinvention, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate several embodiments of theinvention and together with the description, serve to explain theprinciples of the invention.

FIG. 1 is a short-axis view of the heart at the level of the rightatrium (RA) and left atrium (LA), in a plane generally parallel to theatrio-ventricular groove, and at the level of the aortic valve, showinga PFO track.

FIG. 2 is a cross-sectional view of the PFO track of FIG. 1 taken alongline B-B, the PFO in a “closed” configuration.

FIG. 3 is a cross-sectional view of the PFO track of FIG. 2 in an “open”configuration.

FIG. 4 is cross-sectional view of the PFO track of FIG. 1 taken alongline C-C.

FIG. 5 is a perspective view of an abrasion device, according to anaspect of the present invention.

FIG. 6 is a perspective view of the abrasion device of FIG. 5 positionedwithin a PFO track, according to an aspect of the present invention.

FIG. 7 is a cross-sectional view of the PFO track of FIG. 6, after theabrasion device has been applied, with right atrial pressure reduced topermit closure of the PFO track, according to an aspect of the presentinvention.

FIGS. 8 and 9 are cross-sectional views of a catheter being used toclose a PFO track, according to an aspect of the present invention.

FIG. 10 is a perspective view of an embodiment of a self-flatteningclosure device in an open configuration according to one aspect of thepresent invention.

FIG. 11 is a perspective view of the self-flattening closure device ofFIG. 10 in a closed configuration.

FIGS. 12-14 are cross-sectional views of the self-flattening closuredevice of FIGS. 10 and 11 with a delivery catheter and being deployedwithin a PFO track, according to an aspect of the present invention.

FIG. 15 is a top view of an embodiment of a self-flattening closuredevice according to one aspect of the present invention.

FIG. 16 is an end view of the self-flattening closure device of FIG. 15.

FIG. 17 is a side view of the self-flattening closure device of FIG. 15.

FIG. 18 is an end view of the self-flattening closure device of FIG. 15in a partially flattened condition.

FIG. 19 is an end view of the self-flattening closure device of FIG. 15in a flattened configuration.

FIG. 20 is an end view of the self-flattening closure device of FIG. 15in an alternative flattened configuration.

FIG. 21 is an enlarged perspective view of a strut of theself-flattening closure device of FIG. 15.

FIG. 22 is a side view of the self-flattening closure device of FIG. 15on a delivery catheter and connected to an adhesive lumen, according toan aspect of the present invention.

FIGS. 23-25 are cross-sectional views of the self-flattening closuredevice of FIG. 15, with the delivery catheter of FIG. 22, being deployedwithin a PFO track, according to an aspect of the present invention.

FIG. 26 is a side view of a porous balloon catheter according to oneaspect of the present invention.

FIG. 27 is a cross-sectional view of the porous balloon catheter of FIG.26 in an inflated condition.

FIG. 28 is a cross-sectional view of the porous balloon catheter of FIG.26 in a deflated condition.

FIGS. 29-31 are cross-sectional views of the porous balloon catheter ofFIG. 26 being deployed within a PFO track, according to an aspect of thepresent invention.

FIG. 32 is a longitudinal cross-sectional view of a portion of theporous balloon catheter of FIG. 26 filling and sealing the PFO trackafter deployment, according to an aspect of the present invention.

FIG. 33A is a cross-sectional view of an alternative embodiment of aporous balloon in an inflated condition according to another aspect ofthe invention.

FIG. 33B is a longitudinal cross-sectional view of the porous balloon ofFIG. 33A connected to a catheter.

FIG. 34 is a side view of a porous balloon catheter according to oneaspect of the present invention.

FIG. 35 is a first longitudinal cross-sectional view of the balloon ofFIG. 34.

FIG. 36 is a second longitudinal cross-sectional view of the balloon ofFIG. 34 taken from an opposite side than FIG. 35.

FIG. 37 is a cross-sectional view of the porous balloon of FIG. 34 in adeflated condition.

FIG. 38 is a cross-sectional top view of the porous balloon of FIG. 34in the deflated condition and taken along line A-A of FIG. 37.

FIG. 39 is a cross-sectional view of a PFO closure device according toanother aspect of the present invention.

FIGS. 40-42 are cross-sectional views of the PFO closure device of FIG.39 in use to close a PFO track, according to an aspect of the presentinvention.

FIG. 43 is a cross-sectional view of an alternative PFO closure devicedisposed within the right atrium, according to an aspect of the presentinvention.

FIG. 44 is a cross-sectional view of an anchor and suture used with thePFO device of FIG. 43, according to an aspect of the present invention.

FIG. 45 is a cross-sectional view of the anchor and suture of FIG. 44after they have been deployed to close the PFO track, according to anaspect of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to embodiments of the invention,examples of which are illustrated in the accompanying drawings. Whereverpossible, the same reference numbers will be used throughout thedrawings to refer to the same or like parts.

The various figures show embodiments of patent foramen ovale (PFO)closure devices and methods of using the devices to close a PFO. Thedevices and related methods are described herein in connection with usein sealing a PFO. These devices, however, also are suitable for closingother openings or passageways, including other such openings in theheart, for example atrial septal defects, ventricular septal defects,and patent ductus arterioses, and openings or passageways in otherportions of a body such as an arteriovenous fistula. The inventiontherefore is not limited to use of the inventive closure devices toclose PFOs.

According to one aspect of the present invention, an abrasion device isprovided. As embodied herein and shown in FIG. 5, an abrasion device 10is provided for use in a method of closing a PFO track (referenced asPFO in the Figs.). The abrasion device 10 preferably includes aninflatable balloon 12 having a plurality of abrasive elements 14attached to an outer surface of the balloon 12. The abrasive elements 14protrude beyond the outer surface of the balloon 12 and may form asurface similar to that of sandpaper. The abrasive elements 14 may beformed by abrasive material, for example microbeads, attached to theouter surface of the balloon 12 with an adhesive. Alternatively, theabrasive elements may be formed by any other suitable means. Theadhesive should be strong enough to ensure that the abrasive materialcannot come loose during contact with structures within the body, andshould be flexible enough such that it does not inhibit the ability ofthe balloon to be inflated and deflated. An example of a preferredadhesive is a flexible adhesive such as polyurethane or epoxy.

Alternatively, the abrasive elements may be formed by a plurality ofsmall protuberances molded on the outside of the balloon, such that theouter surface of the balloon 12 has an abrasive quality once it isinflated. The abrasion device 10 need not utilize a balloon 12, butcould be fabricated of an expandable material having an abrasive qualityor a non-expandable tube-like element with an abrasive quality.

The abrasion device 10 is attached to a catheter 16 (FIG. 6), whichcontains a lumen (not shown) for inflating and deflating the balloon 12.The abrasion device 10 is passed from an access site, preferably in thefemoral vein, into the PFO track. The abrasion device 10 may be enclosedwithin a distal end of the catheter during passage to the PFO track soas to prevent damage to internal structures of the patient. Oncepositioned near the PFO track, the abrasion device 10 may be moveddistally relative to the end of the catheter by any suitable means knownin the art. The abrasion device 10 is then inflated to place theabrasive elements 14 in contact with the tissue defining the PFO track,as shown in FIG. 6. Portions of the SP and SS which define the PFO trackare then abraded with the abrasion device 10, for example, by rotatingthe abrasion device 10 within the PFO track or a linear back and forthmotion of device 10 in the PFO track. Abrading the tissue surfaces ofthe PFO track denudes the endothelium on these tissue surfaces, settingup a healing response in the tissue and tending to cause the PFO trackto heal closed over time.

Since the patients are typically heparinized during endovascularprocedures, and heparinization may inhibit the adhesion of the tissuesto one another, it may be desirable to counter the effect of the heparinwith protamine, bringing the patient back to a more normal coagulationstate. However, if the heparin is countered, it is desired to have anyremaining devices such as the balloon catheter in the inferior vena cava(IVC) to be coated with an appropriate anti-thrombotic coating such asheparin.

In addition to an adverse heparin effect, other problems may preventadherence between the septum primum (SP) and septum secundum (SS).Various methods are provided herein to enhance or ensure adherencebetween the abraded tissues. For example, during each heart beat, the RApressure may be temporarily higher than the LA, potentially preventingthe denuded tissue surfaces of the PFO track from adhering to oneanother long enough to promote long term healing of the surfaces in anapposed and closed condition. Therefore, a more active closure of thePFO track coupled with the abrading step is preferred, at least for aperiod of several minutes, to assure long-term closure of the PFO track.

One method of causing a more active temporary closure of the PFO trackis illustrated in FIG. 7. After the tissue abrasion step is performed,the abrasion device 10 is removed. Then the venous return to the RA istemporarily reduced. One way to reduce the venous return is totemporarily occlude the inferior vena cava (IVC). This may be performedby positioning an inflatable balloon in the IVC for a period of severalminutes to several hours. The reduction of venous return will reduce thepressure in the RA sufficiently such that the LA pressure will besufficiently greater than the RA pressure, and the greater pressure inthe LA will forcibly push the SP against the SS, closing the PFO track.While held against one another, the denuded tissue surfaces of the SSand SP will quickly pass through the initial stages of the healingresponse and adhere to one another more aggressively than they wouldunder more normal RA pressures.

An alternative active temporary closure method is illustrated in FIGS. 8and 9. In this method, a hollow catheter 16, such as a guiding catheter,is introduced and positioned with its distal end 16 a in contact withthe septum primum SP, at a location near the PFO track, as shown in FIG.8. Once in position, a vacuum is created within the lumen of thecatheter 16. The vacuum sucks or pulls the tissue of the septum primumSP into the end of the catheter 16, anchoring the catheter 16 to theseptum primum SP. The vacuum can be created by any suitable means, suchas with the use of a syringe connected in fluid communication with thelumen of the catheter or via aspiration. Once the catheter 16 isanchored to the septum primum SP, the PFO track is temporarily closed bypulling or otherwise manipulating the catheter 16, as shown in FIG. 9,to pull the septum primum SP into apposition with the septum secundumSS.

After a period of several minutes to several hours has passed as one ofthe above methods is employed, the PFO track will be reliably closedenough to assure the long term healing of the PFO track in a closedcondition. At this point, any indwelling devices can be removed from thepatient. One advantage of this PFO closure technique is that no foreignbody remains in the patient, eliminating issues of foreign bodyreaction, thrombosis, or fatigue failure.

These techniques of abrading the tissue surfaces of the PFO track andtemporarily actively closing the abraded PFO track, as described abovein conjunction with FIGS. 6-9, may be individually combined withadditional closure devices and methods described below.

According to another aspect of the present invention, a PFO closuredevice is provided. As embodied herein and shown generically in FIGS. 10and 11, the PFO closure device comprises a tubular self-flatteningclosure (SFC) device 50. The SFC device 50 is configured to bepositioned and left inside the PFO track. The SFC device 50 may befabricated of a sheet or tube, and may comprise polymeric or preferablymetallic materials, for example, a preferred material is an alloy ofnickel-titanium. Such an alloy can have either shape-memorycharacteristics or super-elastic characteristics when formed and heattreated at particular temperatures, as is known in the art. Preferably,the SFC device 50 is formed under such conditions to create a device 50having a parent shape. The device is preferably formed to have aflattened parent configuration, i.e., a configuration which the devicewill assume when not under other forces, and above itsmartensite-to-austinite transition temperature. This is accomplished byforming and heat treating the device 50 in a flattened configuration.Then, when the device 50 is deformed to a non-flattened configurationduring the delivery steps, it will return to a flattened configurationonce the deforming forces are removed.

The device thus has a first configuration during deployment within thePFO track that is tubular, for example circular, as shown in FIG. 10.The SFC device 50 may be positioned on a balloon catheter, which wheninflated, the balloon holds the SFC device 50 in this configuration.When the balloon is deflated, the SFC device 50 returns to a secondconfiguration, the parent shape resembling a flattened tube, as shown inFIG. 11. Within the PFO track, the flattened configuration is orientedsuch that it tautly maintains a width and a reduced thickness of the PFOtrack, preventing the PFO track from opening during periods of transientelevated RA pressures. Additionally, the SFC device serves to physicallyplug any remaining opening of the PFO track as shown in FIGS. 12-14.

Delivery and deployment of generic SFC device 50 is illustrated in FIGS.12-14. FIG. 12 shows an end view of the PFO track with the SFC device 50in a pre-depolyed condition. The SFC device 50 is wrapped around theuninflated balloon 72 of a balloon catheter 70. The balloon catheter 70with the SFC device 50 is introduced within the venous system, typicallyat an access site in the femoral vein, and positioned within the PFOtrack, as shown. The balloon 72 is inflated to allow the SFC device 50to make contact with the PFO track, as indicated in FIG. 13. When theballoon 72 is deflated and the catheter 70 is removed from the PFOtrack, the SFC device 50 takes on a flattened configuration, as shown inFIG. 14.

A preferred embodiment of an SFC device 150 is shown in FIGS. 15-20.FIG. 15 is a top view of SFC device 150. FIG. 16 is an end view of SFCdevice 150, and FIG. 17 is a side view of SFC device 150. SFC device 150is formed from a metallic tube. Like a vascular stent, portions of thewall of the tube are removed by laser cutting, etching or other processto provide a structure having spaced supports.

As shown in FIG. 15, the SFC device 150 includes a plurality ofcircumferential struts 152. The struts 152 comprise slightly less thanhalf the circumference of the top and bottom sides of the SFC device150. Along SFC device 150, are longitudinal strips 154. Preferably, twostrips 54 are formed, spaced 180 degrees from one another, where cornersof the device 150 are formed when the device is in the flattenedconfiguration. As shown in FIG. 17, the upper and lower struts 152 maybe longitudinally offset from each other. Such a configuration permitsthe SFC device 150 to be shape-set to a flattened configuration suchthat the upper and lower struts 152 don't interfere with each other oncethe device takes on its flattened configuration. That is, when thedevice 150 collapses from a tubular configuration to a flattenedconfiguration, the struts 152 from a top half of the tube fit betweenthe struts 152 of the bottom half of the tube. The offset further allowsthe SFC device 150 to be formed in a parent shape such that the struts152 are actually pushed through or over-set relative to each other (FIG.20). When such a parent shape is deformed in the SFC device 150 due toother forces, as shown in FIG. 18, the device 150 is urged toward aflattened configuration (FIG. 19) with the struts 152 of the top half ofthe device being alternately positioned between struts 152 of the bottomhalf of the device when the other forces are removed. The top and bottomstruts 152 can then actually move past each other in the absence of anyother forces (FIG. 20), i.e., the top struts 152 pass through the spacesbetween the bottom struts 152 until the parent configuration isachieved. By forming the SFC device 150 with such an over-set parentshape, the SFC device 150 more aggressively takes on a flattenedconfiguration when positioned within the PFO track, particularly whenfurther tissue attaching mechanisms are employed, as described below.

According to another aspect of the invention, the SFC device 150 mayinclude an adhesive tissue attaching mechanism. As embodied herein andshown in FIG. 21, at least some of the struts 152 include a hollow lumen156 and may be placed in fluid communication with an adhesive deliverylumen 160 (see FIG. 22). The lumens 156 of struts 152 are in fluidcommunication with a lumen (not shown) which extends within one of thelongitudinal struts 154 of the SFC device 150 and is in fluidcommunication with adhesive delivery lumen 160. Struts 152 may alsoinclude a plurality of outwardly directed holes 158, which provide fordelivery of an adhesive from the struts 152 to the tissue surfacesdefining the PFO track. A preferred adhesive is one that cures uponexposure to moisture, such as a cyanoacrylate. Other suitable adhesives,such as, for example, fibrin glue, a two-part epoxy, or polyurethane,may be used.

In use, the SFC device 150 is positioned on a balloon 172 of a ballooncatheter 170. A detachable tube defines an adhesive delivery lumen 160,and provides for adhesive to be delivered to the lumens of struts 152,154. The delivery lumen 160 is connected to a source of adhesive at aproximal end of the catheter 170, by any suitable means known in theart. The SFC device 150 on the balloon catheter 170, carrying SFC device150, is passed from an access site, preferably in the femoral vein, intothe PFO track (FIG. 23). When the balloon 172 is expanded, as in FIG.24, a suitable adhesive 162 is injected through lumen 160, through thelumen in longitudinal strut 154, into lumens 156 of hollow struts 152until it emerges from the holes 158 and contacts the walls of the PFOtrack. The detachable tube forming lumen 160 is then removed from theSFC device 50 by a suitable detachment mechanism, for example, by abreakaway section that breaks upon torsion. After the adhesive cures,the SFC device 150 is firmly attached to the tissue. Once sufficientcuring has taken place to ensure that the SFC device 150 will remainattached to the walls of the PFO track, the balloon 172 is deflated andthe catheter 170 is removed, allowing the SFC device 150 to flatten(FIG. 25). Since the parent shape is preferably an over-set flattenedshape as described above, the SFC device 150 will aggressively form aflattened shape, bringing the walls of the PFO track, which are adheredto the SFC device 150, in close apposition, and thus closing the PFOtrack (FIG. 25). Over time, additional scar tissue will form within andaround the SFC device 150, creating a long-term robust seal of the PFOtrack. The healing response following implantation of the variousembodiments of the SFC device 150 may be further enhanced by priorabrading of the PFO track, as described above in connection with thedevice of FIG. 5.

Alternatively, it may be possible to deflate and remove the balloon 172and catheter 170 prior to curing of the adhesive. In such a case, theSFC device 150 will flatten prior to the walls of the PFO track adheringto the device 150. Therefore, it would be desirable to use one of themethods described with respect to FIGS. 7-9 to press the walls of thePFO track into the SFC device 150 while the adhesive cures.

According to another aspect of the present invention, an alternative PFOclosure device is provided. As embodied herein and shown in FIGS. 26-32,the PFO closure device may comprise a porous balloon catheter. FIG. 26shows the distal end of a balloon catheter having a porous balloon,herein after referred to as a porous balloon catheter (PBC) 180. PBC 180includes an inflatable balloon 182 having a plurality of small holes 184that perforate the balloon 182. FIG. 27 shows a cross-section of theporous balloon 182 in an inflated state and FIG. 28 shows across-section of the porous balloon 182 in a deflated state. Adetachable tube 186 is connected to a proximal end 188 of the balloon182.

Use of the PBC 180 in closing a PFO track is illustrated in FIGS. 29-32.The PBC 180 is introduced into the venous circulation through standardtechniques, and the balloon 182 is positioned within the PFO track, asshown in FIG. 29. The balloon 182 is then inflated with a fluid thatexhibits adhesive-like qualities once cured. Initially, the balloon 182inflates, expanding the PFO track and making circumferential contactwith the tissue defining the PFO track, as shown in FIG. 30. Furtherpressurization of the balloon 182 then causes some of the liquidadhesive to squeeze out of the pores and form an adhesive film 190between the walls of the PFO and the outer surface of the balloon 182(also shown in FIG. 30). Once the adhesive leaves the balloon 182, itcures upon contact with the moist tissue defining the PFO track. As thecure of the adhesive progresses from the walls of the PFO track towardsthe liquid adhesive inside the balloon 182, the balloon 182 is deflated,bringing the walls of the PFO track, which are now adhered to theballoon 182 via the adhesive film 190, along with it. Once the balloon182 is deflated, a thin film of adhesive remaining on the inside of theballoon 182 is allowed to cure, and the PFO track is closed (FIG. 31),leaving balloon 182 and adhesive 190 therein. The detachable tube 186 isthen removed by a suitable detachment mechanism, such as that describedabove in connection with the removable tube of the SFC device 150. Thebonded-in balloon 182 is left behind in the PFO track (FIG. 32).

The bonded-in balloon 182 will heal in place, resulting in a robustlong-term closure of the PFO track. This closure technique results in aminimum amount of foreign body with virtually no contact with blood ineither the RA or LA, and as with all devices within the presentapplication, little chance or consequence of mechanical fatigue failure.Also, the PBC 180 and method could be combined with a prior abradingstep, as previously described in connection with the device of FIG. 5.

Preferably, the balloon 182 is sized to have a diameter of a sizerelatively similar to the diameter of the PFO track once expanded, i.e.,the perimeter of the balloon is approximately equal to the perimeter ofthe PFO track, and a length equal to or somewhat shorter than the lengthof the PFO track. Suitable biocompatible polymers for the porous balloonare preferably polyethylene, expanded polytetrafluoroethylene, PET,Nylon, silicone, polyurethane, or Pebax. The balloon 182 is preferablyinflatable by a fluid adhesive. A preferred adhesive is one which curesupon exposure to moisture, such as a cyanoacrylate. The adhesive may beprovided to balloon 182 by, for example, a lumen in tube 186 connectedto a source of adhesive.

Alternatively, the balloon 182 of the PBC 180 need not be left in thePFO track. In such an embodiment, the tube 186 need not be detachable.In use, the porous balloon 182 is positioned in the PFO track andinflated as shown in FIGS. 29 and 30. However, the balloon 182 isdeflated and removed prior to curing of the adhesive such that theballoon surface does not adhere to the wall of the PFO track. Thus,after removal of balloon 182, adhesive covers at least some of the wallsof the PFO track. In this embodiment, it is preferred that the adhesivenot cure instantly, but rather take at least a few minutes, providingsufficient time to remove the balloon 182 and catheter 180 withoutcausing adhesion between the balloon 182 and the walls of the PFO track.Suitable adhesives for this embodiment are similar to those discussedabove, but it is important to select an adhesive with a long enough curetime to minimize curing while the balloon 182 is still present in thePFO track.

In addition, in this embodiment where balloon 182 is not left in the PFOtrack, the PFO track may be forced closed utilizing any of the stepsdescribed above in connection with FIGS. 7-9. Once the adhesive issufficiently cured, the venous return can be brought back to normal, ifthe method shown in FIG. 7 is employed, or the catheter with vacuum canbe removed if the method employed in FIGS. 8 and 9 is employed,resulting in a robust closure of the PFO track. In this embodiment, onlya relatively small amount of a biocompatible adhesive is left behind inthe PFO track. And again, for this embodiment, a prior denudation of thewalls of the PFO track may further enhance the robustness of the PFOtrack closure.

According to another aspect of the present invention, an alternativeembodiment of a PFO closure device is provided. As embodied herein andshown in FIGS. 33A and 33B, the PFO closure device comprises a ballooncatheter 280 having a porous balloon 282. Balloon catheter 280 includesa shaft 286 attached to a proximal end 288 of an inflatable balloon 282.The shaft 286 may or may not be detachable. The balloon 282 comprisestwo layers, an inner layer 283 a, which is not porous, and an outerlayer 283 b, which is porous. The dual layer balloon 282 is connected tothe catheter shaft 286, having a first lumen 286 a in fluidcommunication with the interior of the inner layer 283 a, and a secondlumen 286 b in fluid communication with a space 285 between the innerand outer layers 283 a, 283 b. The second lumen 286 b is used fordelivery of an adhesive, while the first lumen 286 a is used forinflation and deflation of the dual layer balloon 282. Since the innerlayer 283 a is non-porous, inflation and deflation of this dual layerballoon 282 can be performed completely independently of adhesivedelivery.

In use, balloon 282 is used in a manner similar to that described abovewith respect to FIGS. 26-30. The balloon 282 is introduced to the PFOtrack, then inflated, and adhesive is delivered via the porous outerlayer 283 b to the walls of the PFO track. The balloon 282 is thendeflated and removed, optionally followed by forced closure of the PFOtrack, as previously described in connection with FIGS. 7-9.Alternatively, the balloon 282 might be detached from the catheter shaftand left implanted in the PFO track as previously described with respectto FIGS. 26-32.

According to another aspect of the present invention, a PFO closuredevice is provided. As embodied herein and shown in FIGS. 34-38, a duallayer porous balloon, similar to the balloon shown in FIGS. 33A and 33B,is provided. In this embodiment, the balloon 382 is connected to adetachable shaft 386. The interior surface 381 of the balloon 382 alsoincludes an adherence mechanism 390. Adherence mechanism 390 preferablyincludes strips of a mechanical interlocking structure, such as Velcro.Strips of Velcro are preferably arranged in a helical fashion on theinterior surface 381 of the balloon 382. The strips are positioned suchthat rows of “hooks” H alternate with rows of “loops” L. The adherencemechanism 390 serves to maintain the balloon 382 in a deflated conditionupon removal of inflation medium from the balloon 382.

FIG. 35 shows the alternating strips of hooks (H) and loops (L) on theinner surface 381 of one half of the balloon 382, and FIG. 36 shows thealternating strips on the inner surface 381 of the opposite half of theballoon 382. When the balloon 382 is deflated, the inner surfaces 381 ofthe two balloon halves come together, forcing the Velcro strips to makecontact in at least a plurality of locations where they intersect (FIGS.37-38).

In use, the porous balloon catheter is used in a similar manner as thatdescribed in connection with the steps shown in FIGS. 26-33B. Theballoon 382 is introduced to the PFO track, inflated at a sufficientlyhigh pressure to disengage the Velcro strips of the adherence mechanism,and adhesive is delivered via the porous outer layer 383 b to the wallsof the PFO track. The balloon 382 is then deflated and the rows ofVelcro on the interior 381 of the balloon 382 come into contact with oneanother, holding the balloon 382 in a flattened configuration. Thecatheter shaft 386 is detached from the balloon 382, and the balloon isleft implanted in the PFO track as previously described with respect toFIGS. 26-32.

According to another aspect of the invention, an alternative embodimentof a PFO closure device is provided. As embodied herein and shown inFIGS. 39-42, the PFO closure device includes a delivery device 400carrying suture-anchor assemblies 401. Each suture-anchor assembly 401includes a barbed anchor 402 connected to a suture tie 404. Suitablesuture tie materials include those typically used in surgical closure ofPFO tracks, such as degradable or non-degradable type commerciallyavailable suture material, monofilament or braided type commerciallyavailable suture material. The barbed anchors 402 and suture ties 404are used to mechanically close the PFO track from within the lumen ofthe PFO track.

The delivery device 400 contains a plurality of suture lumens 406, onefor each suture-anchor assembly 401. Each suture lumen 406 terminates inan opening 408. As shown in FIG. 39, each suture lumen 406 is located onan opposite side of the delivery device 400, such that the suture lumensare spaced approximately 180 degrees apart from one another. Anexpandable head of the delivery device, for example a balloon 410,allows the suture lumen openings 408 to be displaced radially outward.This causes the PFO track to be dilated and stretched taut, whichfacilitates penetration of the anchors into the tissue surrounding thePFO track.

In use, the delivery device 400 is positioned within the PFO track, in anon-deployed condition. The suture-anchor assemblies 401 are positionedwithin the suture lumens 406, with the anchors 402 also residing in thesuture lumens 406. Once the suture lumen openings 408 are in a desiredposition within the PFO track, the expandable head 410 is deployed(i.e., the balloon 410 is inflated). Then the suture-anchor assemblies401 are advanced until the anchors 402 emerge from the suture lumenopenings 408 and penetrate into the tissue forming the PFO track. Toassist in supporting suture anchor assemblies 401 during advancement andpenetration, it may be useful to surround the suture ties 404 with aseparate tubular support members (not shown), which are advanced withthe suture anchor assemblies 401. Tubular support members are removedproximally after anchors 402 are deployed. This step in the procedure isillustrated in FIGS. 39 and 40.

Once the anchors are firmly engaged in the tissue, balloon 410 isdeflated and the delivery device 400 is removed, leaving the sutures 404extending outside the access site of the patient. While two sutures areshown, it is contemplated that any number of sutures, two or more, couldbe placed. The sutures 404 are tied into a knot 412 by any suitablemethod, as shown in FIG. 41, and the knot 412 is pushed towards theanchors 402 with the help of a knot pushing device (not shown). Once theknot 412 is tightened against the walls of the PFO track, the walls arebrought into apposition, and the suture tails are cut, resulting in theconfiguration illustrated in FIG. 42. Cutting of the suture tails can beaccomplished by any suitable endovascular cutting mechanism known in theart.

While these suture and anchor assemblies 401 can be used as a solemechanism for PFO closure, it is preferable to combine this device witha prior abrading of the walls of the PFO track as described previously.When combined as such, the PFO track will heal to a robustly closedcondition.

According to another aspect of the invention, another embodiment of aPFO closure device is provided. As embodied herein and shown in FIGS.43-45, a delivery catheter 500 is positioned within the RA such that thetip 500 a is adjacent the SS, near the PFO track. A suture and anchorassembly 501 comprising a suture 504 with a barb-like anchor 502 isadvanced through the SS, and through the SP, bridging the PFO trackroughly perpendicular to the longitudinal aspect of the PFO track (FIG.43). Suitable suture tie materials include those typically used insurgical closure of PFO tracks, such as degradable or non-degradabletype commercially available suture material, monofilament or braidedtype commercially available suture material. Barb-like anchor 502preferably includes tines 502 a which are self-expanding once theyemerge from the tissue. Once the barb-like anchor 502 is passed throughthe SP, the barb opens up and acts as a strong securement for thesuture. Although only one suture and anchor assembly 501 is illustratedin FIGS. 43-45, more than one may be used as necessary to ensuresufficient closure of the PFO track.

To help facilitate advancement of the suture and anchor assembly 501across the SS and SP, it may be necessary to provide additional supportto the relatively flexible suture 504. FIG. 44 shows a support tube 506surrounding the suture. Support tube 506 preferably has high columnsupport, but enough lateral flexibility to negotiate any curves withinthe delivery catheter 500. Suitable materials include metals andrelatively rigid polymers. Preferred metals include Ni—Ti alloy andstainless steel. Preferred polymers include polyimide and PEEK. Thesupport tube 506 helps advance the anchor 502 and suture 504 across thetissue, and is removed after the anchor is deployed across the SP.

After the barb-like anchor 502 is deployed, a lock device 508,preferably a one-way device, such as, for example, a releasable fixationmechanism (disclosed in U.S. patent application Ser. No. 09/870,813,filed on Jun. 1, 2001, and entitled “Closure Devices, Related DeliveryMethods and Tools, and Related Methods of Use,” the entire disclosure ofwhich is incorporated herein by reference), is advanced along the suture504, pulling the SP and SS together. The remaining suture length is thencut by suitable techniques. While this suture-based concept may beperformed as a sole therapy it is preferable to combine this sutureclosure with a prior abrading of the tissue forming the PFO track tofacilitate a robust long-term closure of the PFO.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. The specification and examples areexemplary, with a true scope and spirit of the invention being indicatedby the following claims.

1. A method of treating a patent foramen ovale in a heart, the methodcomprising: advancing a catheter device having a proximal end and adistal end through vasculature of a patient to position the distal endadjacent the patent foramen ovale; delivering a self-closing closuredevice from the catheter to contact tissues adjacent the patent foramenovale, wherein the delivered self-closing closure device closes to bringtogether the tissues of the patent foramen ovale, and wherein deliveringthe self-closing closure device comprises driving multiple tissueattachment members coupled with a self-closing stent into the tissues;and wherein the self-closing stent comprises a generally tubular memberthat collapses upon itself.
 2. The method of claim 1, wherein theclosure device is biodegradable.
 3. The method of claim 1, furthercomprising extending a portion of the at least one closure device withinthe patent foramen ovale to apply lateral force to tissue at oppositesides of the patent foramen ovale, thus bringing together tissue betweenthe opposite sides.
 4. The method of claim 1, further comprising passingthe catheter body over a guidewire.
 5. The method of claim 1, furthercomprising visualizing at least one of the patent foramen ovale andtissue surrounding the patent foramen ovale with at least onevisualization device coupled with the catheter body near the distal end.